The mystery of who forged the fake Hitler Diaries took a new and possibly final twist yesterday with the confession by a trained graphologist and dealer in Nazi relics that he had written the 62 volumes himself.

After Mr Konrad Kujau, aged 44, told the Hamburg public prosecutor that he had forged the documents after two years of practising Hitler's handwriting, police arrested Mr Gerd Heidemann, the former Stern reporter who said he bought the diaries from Mr Kujau.

The public prosecutor said that Mr Kujau's confession had brought new evidence against Mr Heidemann, which indicated that the 51-year-old reporter knew all along that the diaries were fakes and that his story of having tracked down the documents in East Germany was false.

Mr Heidemann's lawyer later described as "completely absurd" Mr Kujau's claim that the reporter not only knew about the forgeries, but also supplied the paper on which the diaries were written, as well as some of the covers in which they were bound.

Mr Heidemann is facing charges of withholding information and of fraud.

His claim that he paid Mr Kujau the full nine million marks (£2.3 million) he obtained from Stern for the diaries was contradicted by Mr Kujau, who told the public prosecutor that he received only about a quarter of that sum.

But there are also some contradictions in the conduct of Mr Kujau, who has in the meantime been branded by Stern as a "liar" and Nazi sympathiser. On his arrest two weeks ago, he said he could not possibly have forged the diaries because he could neither read nor write the old German script in which they were written.

He also maintained that he had been duped by two East Germans, who, he said, supplied the documents, and revised an earlier statement that he had received the diaries from a relative who was a general in the East German army.

According to Stern, Mr Heidemann had told them the first volumes were obtained from unknown suppliers in an elaborate exchange between passing cars on the East German motorway between West Germany and Berlin.

According to Mr Heidemann, he threw bags of money into a car driving along the motorway while overtaking it, and the diary volumes were thrown through his own window in return.

The reporter said he told Mr Kujau this method of exchange was too dangerous, and the dealer promptly obliged with alternative arrangements which, he claimed, included smuggling the diaries out of East Germany inside pianos.